Follow-up from "Fix inconsistent behaviour in design comments"

The following discussion from !111449 (merged) should be addressed:

• @mrincon started a discussion: (+2 comments)

  Suggestion (for follow-up): We could check the response for errors here instead of leaving it to the parents, both of the them have to do this:

  if (hasErrors(data.updateNote)) {
    this.$emit('error', data.errors[0]);
  }

  Which is something this component could do to reduce duplication.

  This was not introduced here, but I think it better encapsulated error handling logic.